Remove pydocstyle version restriction
Remove pydocstyle version restriction

Ignore the newly added error D999 for __all__ in pywikibot/__init__.py.[1]
This patch also fixes the current flake8 InvocationError.

[1]: https://gitlab.com/pycqa/flake8-docstrings/merge_requests/12/diffs

Bug: T178138
Bug: T184164
Change-Id: I3a6807e0419786e16b7281f9d19bd15fa780c6e2

PersianWikipedia/pywikibot-core,wikimedia/pywikibot-core,wikimedia/pywikibot-core,magul/pywikibot-core,magul/pywikibot-core